1. Field of the Invention
The present invention relates to an apparatus for dispensing vaporizable liquids and an associated detecting element for vaporized liquid.
2. Brief Description of the Background of the Invention Including Prior Art
Petroleum, gasoline, or other vaporizable industrial liquids are in general accompanied by inherent dangers based on their properties, such as flammability. Furthermore, these liquids have to match the equipment which uses them. For this reason, it is important, prior to transferring such liquid to a supply tank, to confirm and to distinguish what kind of liquid is employed and to use an element suitable for distinguishing various kinds of vaporized liquids.
Vaporizable liquids have to be transferred under carefully monitored conditions and safety checks in order to prevent accidents in an industrial, commercial, and residential environment. It would be desirable to have an automatic check in order to save labor.
In this motorized age, in particular in the dispensing of diesel to passenger cars with diesel engines, there have occurred an increasing number of errors at motor-vehicle service stations, i.e. the pumping of gasoline by mistake in place of light oil.
Another problem is the occurrence of accidents caused by an erroneous supply of fuel to individual underground tanks, on the occasion of supplying different kinds and grades of fuel to sections provided in an underground tank for the convenience of fuel transfer to a gas-service station by a large-size tank truck.
Oil detection systems can be based on a detection of changes of the electrostatic capacitance of a line caused by penetration and permeation of liquid oil into a sensor formed by a coaxial cable, as is taught in the Japanese Patent Application Laid Open No. 61-142,609 and, alternatively, by an element which optically detects a liquid, such as oil, as is taught in the Japanese Patent Applications Laid Open Nos. 60-209,144 and 60-115,901. These teachings, however, are directed to the sensing of oil as a liquid and are therefore not suitable for detecting of leaked oil or vaporized liquids in the surroundings and input ports of an oil tank supply.
U.S. Pat. No. 4,838,323 to Andrew J. Watts teaches a system for preventing the accidental addition of automotive fuel to the fuel tank of a gasoline-fuelled vehicle at retail filling stations. A nozzle with sensor system is connected to a processor and the processor is connected to a display. When a diesel fuel tank is erroneously connected to a gasoline delivery pump, the pump will be disconnected if the value of the vapor pressure is below a predetermined value, which means the tank already contains diesel fuel.